Specialized metabolites, also termed natural products (NPs), such as polyketides, non-ribosomal peptides (NRPs), and ribosomally synthesized and post-translationally modified peptides (RiPPs), are critical for microbial interactions and thus gut microbiome dynamics. Despite advances in sequencing and bioinformatic prediction of biosynthetic gene clusters (BGCs), the functional characterization of gut-derived NPs remains limited. This project investigates the functional roles of NPs, produced by Eubacteriales in the human gut, initially focusing on the model species Blautia wexlerae. We will elucidate structure-function relationships, ecological roles, and molecular mechanisms of NPs through a multidisciplinary approach. Using Direct Pathway Cloning (DiPaC), we will produce and characterize all NPs encoded by BGCs in B. wexlerae to foster a global understanding of their importance for the producer strain. Functional studies will involve antimicrobial assays, zebrafish toxicity tests, and the use of defined microbial communities to assess microbe-microbe and microbe-host interactions. Genetic engineering, including knockout mutants and transposon mutant libraries, will uncover mechanisms of NP sensitivity and resistance. In vivo studies in gnotobiotic mice, combined with proteomics and metabolomics, will clarify ecological impacts. This project will establish B. wexlerae as a model for studying gut microbial NPs, advancing our understanding of their roles in microbiome dynamics and host health.